Can I use Perl regular expressions to match balanced text?

   Although Perl regular expressions are more powerful than
   "mathematical" regular expressions because they feature
   conveniences like backreferences ("\1" and its ilk),  
   they still aren't powerful enough--with the possible 
   exception of bizarre and experimental features in the 
   development-track releases of Perl. You still need to 
   use non-regex techniques to parse balanced text, such as 
   the text enclosed between matching parentheses or 
   braces, for example.

   An elaborate subroutine (for 7-bit ASCII only) to pull 
   out balanced and possibly nested single chars, like "`" 
   and "'", "{"and "}", or "(" and ")" can be found in
            http://www.perl.com/CPAN/authors/id/TOMC/scripts/pull_quotes.gz

   The C::Scan module from CPAN contains such subs for   
   internaluse, but they are undocumented.